With regards to declining membership in the White Council, all one need do is to "throw" some of the tests. As a certain Wizard did some time prior to White Night.
As for the Venatori Umbrorum and the Special Acquisitions Division of the Library of Congress... Whose to say that the SAD (or even the entire LoC) isn't part of the Venatori Umbrorum? Particularly if one wants to take the idea of "Masons with Flamethrowers" idea even further, alongside the some of the various stories regarding the founding of the US and/or the Founding Fathers.